A steam turbine blade is eroded by impact behavior given by fine solid particles composed mostly of a condensed water droplet and an iron oxide in steam, so that a surface of the steam turbine blade may be worn. Thus, an erosion resistant layer is sometimes formed on a leading edge portion that is in front of the steam turbine blade (an upstream side of steam flow). As a result, erosion of the steam turbine blade is reduced.
PTL 1 discloses a technique of reducing erosion wear by joining an erosion shield provided in its surface with a boriding layer to a base element of a steam turbine blade. In addition, PTL 2 describes a blade leading edge portion that is a part of a blade shape of a turbine rotary blade, and that is cut off so that an erosion prevention part is restored in the blade leading edge portion by using build-up welding with laser.